[PATCH v2 6/6] ima: Fix return value of ima_write_policy()

[Mimi Zohar]

Hi Roberto,

On Mon, 2020-04-27 at 12:31 +0200, Roberto Sassu wrote:
> This patch fixes the return value of ima_write_policy() when a new policy
> is directly passed to IMA and the current policy requires appraisal of the
> file containing the policy. Currently, if appraisal is not in ENFORCE mode,
> ima_write_policy() returns 0 and leads user space applications to an
> endless loop. Fix this issue by denying the operation regardless of the
> appraisal mode.
> 
> Changelog
> 
> v1:
> - deny the operation in all cases (suggested by Mimi, Krzysztof)

Relatively recently, people have moved away from including the
"Changelog" in the upstream commit. (I'm removing them now.)  

> 
> Cc: stable at vger.kernel.org # 4.10.x
> Fixes: 19f8a84713edc ("ima: measure and appraise the IMA policy itself")
> Signed-off-by: Roberto Sassu <roberto.sassu at huawei.com>

Without the Changelog, the only way of acknowledging people's
contributions is by including their tags.  Krzysztof, did you want to
add your "Reviewed-by" tag?

> ---

People have started putting the Changelog or any comments immediately
below the separator "---" here.

thanks,

Mimi

>  security/integrity/ima/ima_fs.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
> index 8b030a1c5e0d..e3fcad871861 100644
> --- a/security/integrity/ima/ima_fs.c
> +++ b/security/integrity/ima/ima_fs.c
> @@ -338,8 +338,7 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
>  		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL,
>  				    "policy_update", "signed policy required",
>  				    1, 0);
> -		if (ima_appraise & IMA_APPRAISE_ENFORCE)
> -			result = -EACCES;
> +		result = -EACCES;
>  	} else {
>  		result = ima_parse_add_rule(data);
>  	}